The present invention relates to a temperature measuring method and apparatus in a semiconductor processing apparatus which performs heating and cooling, and a semiconductor processing method and apparatus and, more particularly, to a temperature measuring method and apparatus which are used for an RTP (Rapid Thermal Process) or the like to measure a wafer temperature in-situ, and a semiconductor processing method and apparatus.
Semiconductor integrated circuit manufacturing processes include various types of thermal processes such as a baking process, film forming process, ashing process, and the like in photolithography. Conventionally, in the thermal processes, a halogen lamp arranged to face a target substrate (semiconductor wafer) emits light to heat the target substrate. The temperature of the target substrate is measured in the non-contact manner by using a radiation thermometer arranged opposite to the halogen lamp through the target substrate. The light quantity of the halogen lamp is adjusted on the basis of the measurement result, so the heating temperature of the target substrate is controlled.
Since the radiation thermometer conventionally used for temperature measurement receives energy radiated from the surface from an object with a light-to-energy converting element, it can measure the surface temperature of the object in the non-contact manner. Also, the temperature range where the radiation thermometer is used is as wide as about 100xc2x0 C. to 3,000xc2x0 C.
While the radiation thermometer needs the emissivity of the surface of the object for temperature measurement, this emissivity cannot be measured accurately, and the temperature measurement precision is accordingly as low as about 5xc2x0 C. to 20xc2x0 C. In particular, when the object is heated or cooled at a high speed, since the emissivity largely depends on the temperature, accurate temperature measurement is difficult to perform.
Also, the emissivity depends on the temperature, the wavelength of light, the type and thickness of the film forming material in CVD (Chemical Vapor Deposition), and the like.
It is also difficult to calibrate the radiation thermometer. A radiation thermometer that measures a temperature while measuring the emissivity is very expensive.
It is the main object of the present invention to provide a temperature measuring method and apparatus with high measurement precision.
It is another object of the present invention to provide an inexpensive semiconductor processing method and apparatus.
In order to achieve the above objects, a temperature measuring method according to the present invention is a temperature measuring method for a target substrate to be thermally processed in a semiconductor processing apparatus under a predetermined process condition, and includes the steps of detecting a heat flux supplied from at least part of the target substrate to a sensor facing the target substrate and detecting a temperature of the detector, and calculating a temperature of the target substrate from a parameter, including a thermal resistance between the sensor and the target substrate under the predetermined process condition, the detected heat flux, and the temperature of the sensor. The sensor may be arranged opposite to heating means, through the target substrate, which heats the target substrate. The parameter may be obtained in advance by calibration.
A temperature measuring apparatus according to the present invention is a temperature measuring apparatus for a target substrate to be thermally processed in a semiconductor processing apparatus under a predetermined process condition, and comprises heat flux detecting means, having a sensor arranged to face the target substrate, for detecting a heat flux supplied to the sensor from at least part of the target substrate, temperature measuring means for measuring a temperature of the sensor, and calculating means for calculating the temperature of the target substrate from a parameter, including a thermal resistance between the sensor and the target substrate under the predetermined process condition, the detected heat flux, and the temperature of the sensor. The sensor may be arranged opposite to heating means, through the target substrate, which heats the target substrate. The parameter may be obtained in advance by calibration.
A semiconductor processing apparatus according to the present invention comprises heating means for heating a target substrate, temperature measuring means for measuring a temperature of the target substrate to be thermally processed by the heating means, and control means for controlling the heating means on the basis of a measured temperature, to thermally process the target substrate under a predetermined process condition. In this semiconductor processing apparatus, the temperature measuring means is any one of the temperature measuring apparatuses described above. The temperature measuring means also comprise a plurality of temperature measuring means. These temperature measuring means measure temperatures of respective areas of the target substrate divided into a plurality of areas. The control means control the heating means on the basis of the temperatures of the respective areas of the target substrate which are measured by the temperature measuring means. The heating means are controlled to heat one or the plurality of areas of the target substrate divided into the plurality of areas. The semiconductor processing apparatus have storage means for storing, for each of a plurality of different process conditions, a parameter including a thermal resistance between the detector and at least the target substrate under the process condition. The calculating means of the temperature measuring means calculate the temperature of the target substrate for each of the different process conditions on the basis of a parameter corresponding to a current process condition read out from the storage means.
A semiconductor processing method according to the present invention is a semiconductor processing method of thermally processing a target substrate in a semiconductor processing apparatus under a predetermined process condition, including the steps of measuring a temperature of the target substrate to be thermally processed by heating means, and controlling the heating means on the basis of a measured temperature. The step of measuring the temperature of the target substrate includes measuring the temperature of the target substrate in accordance with either one temperature measuring method described above. The detector for detecting the heat flux comprises a plurality of detectors to correspond to respective areas of the target substrate divided into a plurality of areas, and measure temperatures of the respective areas of the target substrate. The step of controlling the heating means comprises controlling the heating means on the basis of the temperatures of the respective areas of the target substrate, thereby heating one or the plurality of areas of the target substrate divided into the plurality of areas. The storage means store, for each of a plurality of different process conditions, a parameter including a thermal resistance between at least the detector and the target substrate under the process condition. The step of measuring the temperature of the target substrate to be thermally processed by the heating means comprises measuring the temperature of the target substrate for each of the different process conditions on the basis of a parameter corresponding to a current process condition read out from the storage means.
With this arrangement, according to the present invention, a heat flux and temperature of one portion are measured, and the temperature of the target substrate is calculated on the basis of them. Accordingly, higher-precision temperature measurement than in the prior art can be performed. No expensive radiation thermometer need be used. As a result, an inexpensive temperature measuring apparatus and a semiconductor processing apparatus using it can be provided.